The present invention comprises a closure system for use on beverage bottles and more particularly discloses a bottle cap assembly for use on carbonated beverage bottles, which assembly maintains carbonation in the beverage and likwise provides a means for dispensing the beverage without depleting the carbon dioxide in the beverage bottle.
Carbonated drinks such as colas and fruit drinks are often sold in large plastic containers, often in sizes as large as three liters, which containers are made of a relatively permeable plastic material such as poly(ethyleneterephthalate), commonly called "PET". Bottlers may add as much as four atmospheres of CO2 pressure to the "headspace" of the filled bottle to maintain acceptable levels of carbonation in the soft drink beverage. This also contributes to rigidity of the filled container during shipment and on the grocer's shelves.
Unfortunately, Pet is a relatively permeable plastic for carbonation (CO2), and allows the gas to continuously permeate out through the container wall. In addition, as the volume of beverage in the container is slowly reduced by the consumer, the headspace increases and allows more open volume for CO2 to evolve into from the liquid drink. Also, each time the large container is opened, the CO2 pressure in the headspace is lost into the atmosphere, thereby increasing the rate of loss from the beverage.
Marketing studies have revealed that the average consumer considers a carbonated beverage to be "flat" when it has lost only about fifteen percent (15%) of its original carbonation. Because of CO2 loss through the container walls and through constant evacuation of the headspace, this level usually occurs before the typical two or three liter bottle is completely empty of beverage.
Thus there is a need in the beverage packaging business for means to reduce or prevent the "headspace" CO2 loss and to offset the permeation loss through the container walls.
Conventional closure devices for carbonated beverage bottles suffer several serious disadvantages. For example, the Saponara, U.S. Pat. No. 4,033,091, discloses a double-cap apparatus with an inner cap providing a closure member to be threaded onto a beverage bottle. A second threaded assembly, carrying a scissors-operated bellows, is threaded onto the exterior of the inner cap. The Saponara closure device suffers from the disadvantages of being bulky and too tall to fit into many refrigerators; requiring that the cap be removed to pour beverage from the bottle, thereby losing all of the carbonation pressure in the bottle; being expensive to make and having complex structure; providing poor sealing with a single ball checkvalve; and, requiring a large scissors system to get enough mechanical advantage to give any significant pressure gain in the bottle.
U.S. Pat. No. 3,557,986 to Poole discloses a closure system comprising a rubber cap that is stretched over a bottle top and has a rubber chamber formed above or to the side of the top. It suffers from the disadvantage that the resilient body will not hold pressure since internal pressure will expand the cap away from the bottle neck and allow carbonation to bleed off. Also the rubber walls of the device offer little barrier to gas loss through permeation. Other disadvantages of the Poole closure are that the low volume of the chamber and inefficient pumping action of the bulb-type chamber would require many flexings to obtain any significant pressure increase; the rubber material of the bulb would soon fatigue and start to crack as a result of the many flexings and the corrosive nature of carbonated beverages; and, the closure has to be removed each time beverage is dispensed. Each removal evacuates the headspace.
U.S. Pat. No. 4,524,877 to Saxby discloses a screw-on closure cap having a plunger/piston passing through the cap and into the bottle. It suffers from the disadvantages of having such a small volume in the piston assembly, which is limited by the size of the bottle neck it must fit into, that it requires an enormous amount of pump strokes to get measurable pressurization in the beverage container; and, the assembly has to be removed in order to pour beverage from the bottle each time.
It should also be noted that none of the conventional devices automatically replace carbonation (CO2 pressure) as it is lost via permeation through plastic container walls. This lost pressure is redeveloped by sacrificing carbonation from the beverage to the headspace. All of the devices require that the closures be removed in order to pour liquids from the bottle, thereby losing all the carbonation in the "headspace" of the bottle.
In addition to the conventional closure devices described above, several apparatus for generating carbonated beverage from plain water are known commercially. For example, U.S. Pat. Nos. 4,306,667, 4,359,432, and 4,376,496, all to Sedam et al, disclose large and complex commercial-scale carbonated beverage generating systems utilizing a large plain-water reservoir, a carbonating device, and the primary feature which is a "disposable package for containing and dispensing the syrup of the post-mix beverage". These do not disclose apparatus usable as closures on carbonated beverage bottles.
The present invention overcomes these disadvantages by providing a compact closure assembly that allows for continuous repressurization of the beverage, provides a pressurized dispensing system, and does not allow the headspace carbonation to be depleted every time beverage is dispensed. It performs these functions by the provision of a bottle closure system having separate pressurization flow means and fluid dispensing means, and an external pressure generation system. The invention optionally provides an external dispenser control device.